On Birth Control And Took Plan B

I've been off and on birth control (ortho tri-cyclen lo) for about 2 years now. Recently, at the beginning of this month, I started a new pack after being off of birth control for about 3 or 4 months. I am very intune with my body, I can tell when i'm ovulating, when my period is ready to come, etc. On the the third week, monday to be exact, I felt that familiar twinge that is synonymous with ovulation. That tuesday night/early wednesday morning my boyfriend and I had unprotected sex. It didn't occur to me until later that I should not be ovulating because that's what birth control is for, to prevent pregnancy. That friday afternoon, I went to my gyno within the 72 hour period to take plan b or emergency contraception. I continued taking my pills on time everyday as usual and now i'm closing the last week. I usually get my period on thursday of the last week. Today is wednesday and I show no signs of even having a period. I know the boost in extra progestin may cause my period to be late or not come at all, but i'm really worried. Has anyone gone through something like this before and should I worry???